Measuring device and methods for use therewith

Abstract

The ability to switch at will between amperometric measurements and potentiometric measurements provides great flexibility in performing analyses of unknowns. Apparatus and methods can provide such switching to collect data from an electrochemical cell. The cell may contain a reagent disposed to measure glucose in human blood.

1 . A test instrument for use with a human user and for use with an elongated test strip having at a first end an electrical connection point and at a second end an electrochemical cell, the test instrument comprising: 
 a housing;    an electrical connector at the housing, the connector disposed to form an electrical connection with the electrical connection point of an elongated test strip when inserted therein;    a light source at the housing, the light source aimed to cast light upon the electrochemical cell of the elongated test strip, the light source illuminated in response to an input from a human user.    
   
   
       2 . The test instrument of  claim 1  wherein the light source is additionally aimed to cast light upon the electrical connector, the light source illuminated in response to an input from a human user prior to insertion of the electrical connection point of the elongated test strip into the electrical connector.  
   
   
       3 . The test instrument of  claim 1  wherein the light source is a light-emitting diode.  
   
   
       4 . The test instrument of  claim 1  wherein the light source is non-red.  
   
   
       5 . The test instrument of  claim 4  wherein the light source is blue.  
   
   
       6 . A test instrument for use with a human user and for use with an elongated test strip having at a first end an electrical connection point and at a second end an electrochemical cell, the test instrument comprising: 
 a housing;    an electrical connector at the housing, the connector disposed to form an electrical connection with the electrical connection point of an elongated test strip when inserted therein;    a light source at the housing, the light source aimed to cast light upon the electrical connector, the light source illuminated in response to an input from a human user prior to insertion of the electrical connection point of the elongated test strip into the electrical connector.    
   
   
       7 . The test instrument of  claim 6  wherein the light source is additionally aimed to cast light upon the electrochemical cell of the elongated test strip, the light source illuminated in response to an input from a human user.  
   
   
       8 . The test instrument of  claim 6  wherein the light source is a light-emitting diode.  
   
   
       9 . The test instrument of  claim 6  wherein the light source is non-red.  
   
   
       10 . The test instrument of  claim 9  wherein the light source is blue.  
   
   
       11 . A method for use with a test instrument for use with a human user and for use with an elongated test strip having at a first end an electrical connection point and at a second end an electrochemical cell, the method comprising the steps of: 
 inserting the electrical connection point of an elongated test strip into an electrical connector at the test instrument, the connector forming an electrical connection with the electrical connection point of the elongated test strip;    providing a first input from a human user to the test instrument; and    in response to the first input, casting light from a light source at the test instrument upon the electrochemical cell of the elongated test strip.    
   
   
       12 . The method of  claim 11  further comprising the steps, both performed before the inserting step, of: 
 providing a second input from a human user to the test instrument; and    in response to the second input, casting light from the light source upon the electrical connector.    
   
   
       13 . The method of  claim 11  wherein the casting step comprises illuminating a light-emitting diode.  
   
   
       14 . The method of  claim 11  wherein the casting step comprises casting non-red light.  
   
   
       15 . The method of  claim 14  wherein the casting step comprises casting blue light.  
   
   
       16 . The method of  claim 12  wherein the casting steps comprise illuminating a light-emitting diode.  
   
   
       17 . The method of  claim 12  wherein the casting steps comprise casting non-red light.  
   
   
       18 . The method of  claim 17  wherein the casting steps comprise casting blue light.  
   
   
       19 . A method for use with a test instrument for use with a human user and for use with an elongated test strip having at a first end an electrical connection point and at a second end an electrochemical cell, the test instrument comprising an electrical connector disposed to form an electrical connection with the electrical connection point of the elongated test strip, the test instrument further comprising a light source, the method comprising the steps, both performed before any insertion of the electrical connection point of an elongated test strip into the electrical connector, of: 
 providing a first input from a human user to the test instrument; and    in response to the first input, casting light from the light source upon the electrical connector.    
   
   
       20 . The method of  claim 19  further comprising the steps, performed after the providing the first input and after the casting light in response to the first input, of: 
 inserting the electrical connection point of an elongated test strip into an electrical connector at the test instrument, the connector forming an electrical connection with the electrical connection point of the elongated test strip;    providing a second input from a human user to the test instrument; and    in response to the second input, casting light from the light source at the test instrument upon the electrochemical cell of the elongated test strip.    
   
   
       21 . The method of  claim 19  wherein the casting step comprises illuminating a light-emitting diode.  
   
   
       22 . The method of  claim 19  wherein the casting step comprises casting non-red light.  
   
   
       23 . The method of  claim 22  wherein the casting step comprises casting blue light.  
   
   
       24 . The method of  claim 20  wherein the casting steps comprise illuminating a light-emitting diode.  
   
   
       25 . The method of  claim 20  wherein the casting steps comprise casting non-red light.  
   
   
       26 . The method of  claim 25  wherein the casting steps comprise casting blue light.  
   
   
       27 . An elongated test strip having at a first end an electrical connection point and at a second end an electrochemical cell, the test strip further comprising an optical waveguide extending from the first end to the second end, whereby light cast into the waveguide at the first end is emitted from the waveguide at the second end.  
   
   
       28 . The elongated test strip of  claim 27  further comprising a test instrument, the test instrument comprising an electrical connector disposed to form an electrical connection with the electrical connection point of the test strip, the test instrument further comprising a light source disposed to cast light into the waveguide at the first end.  
   
   
       29 . The test strip of  claim 28  wherein the light source is a light-emitting diode.  
   
   
       30 . The test strip of  claim 28  wherein the light source is non-red.  
   
   
       31 . The test strip of  claim 30  wherein the light source is blue.  
   
   
       32 . The test strip of  claim 28  further comprising an input means responsive to a user input for causing the light source to cast the light.  
   
   
       33 . The test strip of  claim 27  wherein the waveguide is substantially transparent.  
   
   
       34 . The test strip of  claim 27  wherein the waveguide is fluorescent.  
   
   
       35 . The test strip of  claim 27  wherein the waveguide is phosphorescent.  
   
   
       36 . The test strip of  claim 27  wherein the elongated test strip has a length, and wherein light cast into the waveguide at the first end is additionally emitted from the waveguide along its length.  
   
   
       37 . A method for use with an elongated test strip having at a first end an electrical connection point and at a second end an electrochemical cell, the test strip further comprising an optical waveguide extending from the first end to the second end, whereby light cast into the waveguide at the first end is emitted from the waveguide at the second end, the method comprising the steps of: 
 casting light into the waveguide at the first end; and    emitting light from the waveguide at the second end.    
   
   
       38 . The method of  claim 37  further comprising the steps of: 
 illuminating a drop of blood by means of the emitted light; and    guiding the electrochemical cell to the drop of blood.    
   
   
       39 . The method of  claim 37  wherein the casting of light comprises illuminating a light-emitting diode.  
   
   
       40 . The method of  claim 38  wherein the casting of light comprises casting non-red light.  
   
   
       41 . The method of  claim 40  wherein the casting of light comprises casting blue light.  
   
   
       42 . The method of  claim 37  wherein the casting of light is in response to a step, performed by a user, of providing a user input further comprising an input means responsive to a user input for causing the light source to cast the light.  
   
   
       43 . The method of  claim 37  wherein the elongated test strip has a length, and wherein the emitting step further comprises emitting light from the waveguide along its length.  
   
   
       44 . A method for use with a test instrument for use with a human user, the test instrument having a display comprising a rectangular array of low-resolution areas, the array comprising first and second axes, the method comprising the steps of: 
 performing at least one electrochemical test with respect to a bodily fluid of a human user;    illustrating first information of interest to the human user by means of the the rectangular array, the information illustrated by means of a first bar graph, the first bar graph having horizontal bars, each horizontal bar within a row of the rectangular array; and    illustrating second information of interest to the human user by means of the the rectangular array, the information illustrated by means of a second bar graph, the second bar graph having vertical bars, each vertical bar within a column of the rectangular array.    
   
   
       45 . The method of  claim 44  wherein the rectangular array of low-resolution areas comprises six rows and fifteen columns.  
   
   
       46 . A test instrument for use with a human user, the test instrument having a display comprising a rectangular array of low-resolution areas, the array comprising first and second axes, the test instrument comprising: 
 means performing at least one electrochemical test with respect to a bodily fluid of a human user;    means illustrating first information of interest to the human user by means of the the rectangular array, the information illustrated by means of a first bar graph, the first bar graph having horizontal bars, each horizontal bar within a row of the rectangular array; and    means illustrating second information of interest to the human user by means of the the rectangular array, the information illustrated by means of a second bar graph, the second bar graph having vertical bars, each vertical bar within a column of the rectangular array.    
   
   
       47 . The test instrument of  claim 46  wherein the rectangular array of low-resolution rectangles comprises six rows and fifteen columns.  
   
   
       48 . The test instrument of  claim 46  wherein the display is a liquid-crystal display and wherein each of the low-resolution areas has a respective conductive trace to a connection point from the display to other circuitry.  
   
   
       49 . A method for use in a handheld test equipment apparatus having an electrochemical cell disposed to receive a bodily fluid of a human user, the apparatus comprising electronic circuitry, the method comprising the steps of: 
 under automatic control of the electronic circuitry, passing electrical current through the cell by means of a current source external to the cell and measuring said current;    thereafter, under automatic control of the electronic circuitry, ceasing the passage of electrical current from the current source external to the cell;    thereafter, under automatic control of the electronic circuitry, measuring an electrical potential at the cell; and    evaluating a function of the measured current and the measured electrical potential, whereby a measure of characteristic of the bodily fluid is evaluated.    
   
   
       50 . The method of  claim 49  wherein the bodily fluid is blood.  
   
   
       51 . The method of  claim 50  wherein the electrochemical cell comprises a reagent reactive with glucose, and the evaluated characteristic of the blood is a concentration of glucose in the blood.  
   
   
       52 . The method of  claim 49  wherein the bodily fluid is urine.  
   
   
       53 . The method of  claim 49  wherein the passing of electrical current through the cell comprises passing a constant current through the cell.  
   
   
       54 . The method of  claim 53  wherein the measurement of the current comprises measuring the duration of the current.  
   
   
       55 . The method of  claim 49  wherein the passing of electrical current through the cell comprises applying a constant current through the cell.  
   
   
       56 . The method of  claim 49  wherein the passing of electrical current through the cell comprises applying a time-variant voltage to the cell.  
   
   
       57 . The method of  claim 56  wherein the non-constant voltage applied to the cell comprises a sinusoidal potential.  
   
   
       58 . The method of  claim 56  wherein the non-constant voltage applied to the cell comprises a ramp potential.  
   
   
       59 . The method of  claim 49  wherein the test equipment comprises a housing and the electrochemical cell is within a test strip external to the housing, the method further comprising the steps, performed before the step of passing current through the cell, of: 
 inserting the test strip into a connector at the housing, and    applying the bodily fluid to the electrochemical cell.    
   
   
       60 . The method of  claim 59  further comprising the step, performed after the step of measuring an electrical potential at the cell, of: 
 removing the test strip from the housing.    
   
   
       61 . The method of  claim 49  wherein the electrochemical cell comprises at least first and second electrodes, and wherein the step of ceasing the passage of electrical current from the current source external to the cell further comprises: 
 opening a first switch whereby at least the first electrode of the electrochemical cell is isolated from the current source external to the cell.    
   
   
       62 . The method of  claim 61  wherein the step of ceasing the passage of electrical current from the current source external to the cell further comprises: 
 opening a second switch whereby at least the second electrode of the electrochemical cell is isolated from the current source external to the cell.    
   
   
       63 . The method of  claim 61  wherein the first electrode comprises a working electrode.  
   
   
       64 . The method of  claim 63  wherein the second electrode comprises a reference electrode.  
   
   
       65 . The method of  claim 63  wherein the second electrode comprises a counter electrode.  
   
   
       66 . The method of  claim 61  wherein the first electrode comprises a reference electrode.  
   
   
       67 . The method of  claim 66  wherein the second electrode comprises a working electrode.  
   
   
       68 . The method of  claim 66  wherein the second electrode comprises a counter electrode.  
   
   
       69 . The method of  claim 61  wherein the first electrode comprises a counter electrode.  
   
   
       70 . The method of  claim 69  wherein the second electrode comprises a reference electrode.  
   
   
       71 . The method of  claim 69  wherein the second electrode comprises a working electrode.  
   
   
       72 . The method of  claim 63  wherein the step of measuring an electrical potential at the cell comprises measuring a potential between the working electrode and a reference electrode.  
   
   
       73 . The method of  claim 63  wherein the step of measuring an electrical potential at the cell comprises measuring a potential between the working electrode and a counter electrode.  
   
   
       74 . The method of  claim 66  wherein the step of measuring an electrical potential at the cell comprises measuring a potential between the reference electrode and a working electrode.  
   
   
       75 . The method of  claim 66  wherein the step of measuring an electrical potential at the cell comprises measuring a potential between the reference electrode and a counter electrode.  
   
   
       76 . The method of  claim 69  wherein the step of measuring an electrical potential at the cell comprises measuring a potential between the counter electrode and a reference electrode.  
   
   
       77 . The method of  claim 69  wherein the step of measuring an electrical potential at the cell comprises measuring a potential between the counter electrode and a working electrode.  
   
   
       78 . A handheld test equipment comprising: 
 an electrochemical cell comprising a reagent reactive with a constituent of a human bodily fluid;    a current source external to the electrochemical cell;    a potentiometric circuitry external to the electrochemical cell;    electronic control means;    the electronic control means coupled with the current source to controllably apply the current source to the electrochemical cell, thereby passing current through the cell;    amperometric means external to the electrochemical cell for measuring the current passed through the electrochemical cell;    the electronic control means coupled with the potentiometric circuitry to automatically cease application of the current through the electrochemical cell, and then to measure a potential at the electrochemical cell in the absence of the applied current.    
   
   
       79 . The handheld test equipment of  claim 78  further comprising a housing and a test strip external to the housing and electrically connected to a connector at the housing, the housing containing the current source, the potentiometric circuitry, and the electronic control means, the test strip comprising the electrochemical cell.  
   
   
       80 . The handheld test equipment of  claim 78  wherein the electrochemical cell comprises at least a first and second electrode, the potentiometric circuitry disposed to measure potential at the first and second electrode.  
   
   
       81 . The handheld test equipment of  claim 80  wherein the first electrode comprises a working electrode.  
   
   
       82 . The handheld test equipment of  claim 81  wherein the second electrode comprises a reference electrode.  
   
   
       83 . The handheld test equipment of  claim 81  wherein the second electrode comprises a counter electrode.  
   
   
       84 . The handheld test equipment of  claim 80  wherein the first electrode comprises a counter electrode.  
   
   
       85 . The handheld test equipment of  claim 84  wherein the second electrode comprises a reference electrode.  
   
   
       86 . The handheld test equipment of  claim 84  wherein the second electrode comprises a working electrode.  
   
   
       87 . The handheld test equipment of  claim 80  wherein the first electrode comprises a reference electrode.  
   
   
       88 . The handheld test equipment of  claim 87  wherein the second electrode comprises a working electrode.  
   
   
       89 . The handheld test equipment of  claim 87  wherein the second electrode comprises a counter electrode.  
   
   
       90 . The handheld test equipment of  claim 80  further comprising a first switch selectively disconnecting the first electrode from the current source, the ceasing of application of current to the electrochemical cell comprising opening the first switch.  
   
   
       91 . The handheld test equipment of  claim 90  further comprising a second switch selectively disconnecting the second electrode from the current source, the ceasing of application of current to the electrochemical cell further comprising opening the second switch.  
   
   
       92 . The handheld test equipment of  claim 78  wherein the current source comprises a constant-current source.  
   
   
       93 . The handheld test equipment of  claim 78  wherein the current source comprises a source of time-variant current.  
   
   
       94 . The handheld test equipment of  claim 93  wherein the current source comprises a source of sinusoidal current.  
   
   
       95 . The handheld test equipment of  claim 93  wherein the current source comprises a source of ramp current.  
   
   
       96 . The handheld test equipment of  claim 93  wherein the current source comprises a digital-to-analog converter.  
   
   
       97 . The handheld test equipment of  claim 93  wherein the current source comprises a pulse-width-modulated signal.  
   
   
       98 . The handheld test equipment of  claim 97  wherein the pulse-width-modulated signal is applied to a capacitor.  
   
   
       99 . The handheld test equipment of  claim 78  further comprising means logging the potential measurements and deriving a function of the logged measurements indicative of the constituent of the bodily fluid.  
   
   
       100 . The handheld test equipment of  claim 78  wherein the bodily fluid is blood.  
   
   
       101 . The handheld test equipment of  claim 78  wherein the bodily fluid is urine.  
   
   
       102 . The handheld test equipment of  claim 100  wherein the reagent is reactive with glucose, and the constituent of the bodily fluid is glucose.  
   
   
       103 . The handheld test equipment of  claim 99  wherein the means is within the housing.  
   
   
       104 . The handheld test equipment of  claim 99  wherein the means is outside the housing.  
   
   
       105 . The handheld test equipment of  claim 99  further comprising a display means communicatively coupled with the deriving means for displaying to a human user an indication of the constituent of the bodily fluid.  
   
   
       106 . The handheld test equipment of  claim 105  wherein the display means is outside the housing.  
   
   
       107 . The handheld test equipment of  claim 105  wherein the display means is within the housing.  
   
   
       108 . A handheld test equipment comprising: 
 a housing;    a connector at the housing having at least first and second contacts;    a current source;    a potentiometric circuitry within the housing;    electronic control means within the housing;    the electronic control means coupled with the current source to controllably apply the current source to the at least first and second contacts;    amperometric means within the housing for measuring the current passed through the at least first and second contacts;    the electronic control means coupled with the potentiometric circuitry to automatically cease application of the current to the at least first and second contacts, and then to measure a potential at the at least first and second contacts in the absence of the applied current.    
   
   
       109 . The handheld test equipment of  claim 108  further comprising a test strip external to the housing and electrically connected to the connector at the housing, the test strip comprising an electrochemical cell, the electrochemical cell in electrical connection with the at least first and second contacts.  
   
   
       110 . The handheld test equipment of  claim 109  wherein the electrochemical cell comprises at least a first and second electrode electrically connected with the at least first and second contacts respectively, the potentiometric circuitry disposed to measure potential at the first and second electrode.  
   
   
       111 . The handheld test equipment of  claim 110  wherein the first electrode comprises a working electrode.  
   
   
       112 . The handheld test equipment of  claim 111  wherein the second electrode comprises a reference electrode.  
   
   
       113 . The handheld test equipment of  claim 111  wherein the second electrode comprises a counter electrode.  
   
   
       114 . The handheld test equipment of  claim 110  wherein the first electrode comprises a counter electrode.  
   
   
       115 . The handheld test equipment of  claim 114  wherein the second electrode comprises a reference electrode.  
   
   
       116 . The handheld test equipment of  claim 114  wherein the second electrode comprises a working electrode.  
   
   
       117 . The handheld test equipment of  claim 110  wherein the first electrode comprises a reference electrode.  
   
   
       118 . The handheld test equipment of  claim 117  wherein the second electrode comprises a working electrode.  
   
   
       119 . The handheld test equipment of  claim 117  wherein the second electrode comprises a counter electrode.  
   
   
       120 . The handheld test equipment of  claim 108  further comprising a first switch selectively disconnecting the first contact from the current source, the ceasing of application of current to the at least first and second contacts comprising opening the first switch.  
   
   
       121 . The handheld test equipment of  claim 120  further comprising a second switch selectively disconnecting the second contact from the current source, the ceasing of application of current to the at least first and second contacts further comprising opening the second switch.  
   
   
       122 . The handheld test equipment of  claim 108  wherein the current source comprises a constant-current source.  
   
   
       123 . The handheld test equipment of  claim 108  wherein the current source comprises a source of time-variant current.  
   
   
       124 . The handheld test equipment of  claim 123  wherein the current source comprises a source of sinusoidal current.  
   
   
       125 . The handheld test equipment of  claim 123  wherein the current source comprises a source of ramp current.  
   
   
       126 . The handheld test equipment of  claim 123  wherein the current source comprises a digital-to-analog converter.  
   
   
       127 . The handheld test equipment of  claim 123  wherein the current source comprises a pulse-width-modulated signal.  
   
   
       128 . The handheld test equipment of  claim 127  wherein the pulse-width-modulated signal is applied to a capacitor.  
   
   
       129 . The handheld test equipment of  claim 108  further comprising means logging the potential measurements and deriving a function of the logged measurements indicative of the constituent of a bodily fluid.  
   
   
       130 . The handheld test equipment of  claim 129  wherein the bodily fluid is blood.  
   
   
       131 . The handheld test equipment of  claim 129  wherein the bodily fluid is urine.  
   
   
       132 . The handheld test equipment of  claim 130  constituent of the bodily fluid is glucose.  
   
   
       133 . The handheld test equipment of  claim 129  wherein the logging means is within the housing.  
   
   
       134 . The handheld test equipment of  claim 129  wherein the logging means is outside the housing.  
   
   
       135 . The handheld test equipment of  claim 129  further comprising a display means communicatively coupled with the deriving means for displaying to a human user an indication of the constituent of the bodily fluid.  
   
   
       136 . The handheld test equipment of  claim 135  wherein the display means is outside the housing.  
   
   
       137 . The handheld test equipment of  claim 135  wherein the display means is within the housing.  
   
   
       138 . An apparatus for use with a reaction cell having a first electrode and a second electrode, the apparatus comprising: 
 a voltage source providing a controllable voltage to the first electrode;    a voltage sensor sensing voltage provided to the first electrode;    an amplifier;    switch means switchable between first and second positions, said switch means in said first position disposing the amplifier to measure current through the second electrode, thereby measuring current through the reaction cell, said switch means in said second position disposing the amplifier to measure voltage present at the second electrode.    
   
   
       139 . The apparatus of  claim 128  wherein the switch means comprises first, second, and third analog switches, the first analog switch connecting the second electrode and an inverting input of the amplifier, the second analog switch connecting the second electrode and a non-inverting input of the amplifier, the third analog switch connecting the non-inverting input of the amplifier and a reference voltage, the first position defined by the first and third switches being closed and the second switch being open, the second position defined by the first and third switches being open and the second switch being closed.